One of the OSU defensemen, after tackling the Wisconsin quarterback, tried to choke him. The video that they were showing makes it obvious - after the QB (Sorgi) went down, the defenseman (Reynolds, #44) shoves his hand against his throat and starts pushing hard. (This is evident from body positioning - he's basically on top of the QB.) Eventually another Wisconsin player shoves him off - but Sorgi's throat is injured and he can't speak and is thus unable to call plays for the rest of the game. He has to come out.
Luckily, Wisconsin's backup QB (Schabert) performed admirably, including a 79-yard TD pass. Wisconsin won the game.
I hope Sorgi will be alright. I also hope Reynolds gets suspended - or better, permanently banned - for his blatant attempt to injure another player. Fucker.